An increasing number of web-based Delay Tolerant Network (DTN) applications are being developed by researchers, ranging from monitoring the environment to supplementing other network infrastructure located or installed in harsh environments like wireless sensor networks. These applications need to communicate with the DTN daemon to facilitate data transmission. Hence, it is necessary to provide a middleware layer that allows the communication between applications based on different platforms and DTN service daemons. In this paper, a DTN Service Adaptation Middleware (DSAM) is proposed to provide a communication layer between DTN service daemons and different applications based on different platforms (e.g., Java, Python, C/C++, PHP). Furthermore, we delineate the architecture of DSAM and describe two supporting applications based on our middleware, namely DTN2 network management tool and WSN environmental monitoring application. Finally, we present our findings grounded on performance evaluations in terms of throughput and power consumption.